Advances in the field of electronic devices have led to a concomitant rise in consumer demand for good quality, but inexpensive electronic devices. In particular, the popularity of cellular telephones has increased sharply in response to the improvement in quality of cellular communications and to the reduction in the cost of cellular telephones and their use. In seeking to meet customer demand, manufacturers have sought to produce quality electronic devices in a more efficient and economical manner. To meet and beat the competition, manufacturers have sought to produce quality electronic devices more quickly and less expensively.
With respect to consumer electronic devices, such as cellular telephones, one of the principal problems faced by a manufacturer is the efficient and economical manner of assembly of such devices. Assembly of an electronic device such as a cellular telephone requires the assembly and connection of components such as computer chips onto a printed circuit board. During the research and development of a particular electronic device, the components may be assembled and connected onto a printed circuit board partially or completely by hand. However, large scale production of the electronic device requires a method of circuit board assembly and connection that is quicker than hand assembly, that is higher in quality, and that is more economical.
Prior art systems have turned to automation for circuit board assembly and connection. One particular prior art system is an automatic pick and place machine (also referred to as a "chip mounter", a "chip placement machine", or generally as a "component placement machine"). An example of an automatic pick and place machine is the PANASERT MPA 40 and similar equipment manufactured by Matsushita, Inc., Seike Division, Japan. Comparable pick and place machines are available from other manufacturers. A pick and place machine includes a motorized conveyor belt for delivery of an empty or nearly empty circuit board to a component assembly location. After assembly, the conveyor belt transports the circuit board away from the component assembly location to the next station in the assembly of the electronic device. At the component assembly location, the pick and place machine assembles and connects most of the necessary components onto a circuit board pursuant to a computer program that provides directions for the selection and placement of each component onto the circuit board. Generally, the pick and place machine uses a vacuum mounting head to pick up a component and then to connect it in a particular position on the circuit board. A pick and place machine may use more than one vacuum mounting head in the assembly of the components on the circuit board.
In a pick and place machine, each vacuum mounting head includes a nozzle that directs a vacuum force for picking up a component, holding the component during transport to the component's position on the circuit board, and placing the component in position on the board. A common prior art nozzle is a nozzle that is generally needle shaped in appearance with a hole at the distal end of the needle for application of the vacuum force to pick up and hold each component. Through use of a needle-like nozzle on a vacuum mounting head, a pick and place machine is able to assemble and connect small, light and substantially flat-topped components on a circuit board. Other components have had to be assembled and connected by hand.
As noted above, a prior art needle-like nozzle is able generally to assemble and connect only small, light and substantially flat-topped components. A needle-like nozzle has difficulties in picking up, transporting and positioning large and/or wafer-like components because the disproportionate size of a large and/or wafer-like component with respect to the area of the needle hole does not allow for sufficient vacuum force to be delivered across a large enough surface area to accommodate the large size and/or wafer-like shape of the component. Similarly, a needle-like nozzle has difficulties in picking up, transporting and positioning relatively heavy components because the weight of these components is too much with respect to the vacuum force that the needle-like nozzle directs through its needle hole. In addition, a needle-like nozzle has difficulties in picking up, transporting and positioning components that are not substantially flat-topped because the needle hole is unable to achieve a good vacuum seal with such a component and the vacuum force is lessened, thereby causing difficulties in the handling of the component.
As a result of the inability to properly handle certain components, a vacuum mounting head with a needle-like nozzle may miss certain components during pick up procedures necessitating the repetition of the pick up procedures for that component. Also, the needle-like nozzle may drop a component during transport of the component necessitating the repetition of the pick up and transport procedures for that component. In addition, the needle-like nozzle may misplace a component necessitating the repetition of the pick up, transport and placement procedures. Missing a component on pick up, dropping a component or misplacing the component may bend or break the component and destroy its usefulness. In addition, dropping a component on the circuit board or misplacing a component on the board may destroy the usefulness of other components already placed on the board or the board itself.
Solutions to these problems with needle-like nozzles in vacuum mounting heads have been attempted. One solution has been to increase the size of the hole in the needle-like nozzle. An increase in the needle hole may ameliorate some of the pick up, transport and placement problems, but fails to address other problems such as the problem in picking up, transporting and placing components that are not substantially flat-topped. In addition, an increase in the needle hole adds at least an additional problem in that a nozzle with a large needle hole would be unable to pick up very small components. These components would be sucked up entirely into the nozzle causing a jam in the nozzle, and otherwise negatively affecting the assembly of the electronic device.
Another solution to these assembly problems has been to customize the configuration of a pick and place machine to the particular electronic device that is assembled by the machine. In a customized machine, the mounting heads are specially customized to handle the variety of components used in the particular electronic device. These mounting heads may include vacuum mounting heads, but also may include heads that mount components by other means such as robotic arms or centering fingers. Obviously, a customized pick and place machine is a significant investment for a manufacturer. Further, a customized pick and place machine takes time to develop and build, and this development time slows down the time table for production of the electronic devices. Given the changes that must be made regularly to an electronic device to accommodate technological advances and consumer tastes, the expense and time delays associated with a customized pick and place machine may not be justified.
As a result of the problems with prior art pick and place machines using needle-like nozzles and the expense and time delays associated with customized pick and place machines, manufacturers have employed workers to position certain components on a circuit board of an electronic device. For example, a manufacturer may use a pick and place machine to place the majority of components on a circuit board, and then employ personnel to place large, wafer-like, heavy or odd shaped components on the board by hand.
Such use of personnel to hand place certain components on a circuit board has significant drawbacks. One of the principal drawbacks of the hand method is the time delay that is introduced into the assembly of the electronic device. The whole assembly fine is held up by at least the length of time the worker takes to position a component by hand. Even a very skilled worker cannot pick up, transport and position a component as quickly as the slowest pick and place machine. Another drawback of the hand method is the diminishment in quality with respect to the placement and connection of the component. The overall quality of component placement suffers when done by hand because even a skilled worker is unable to consistently position a component in the best possible position. Further, hand placement results in an increase in the number of broken and damaged components and circuit boards. Another significant drawback is the reduction in the work force that would otherwise be available for more sophisticated work, but for the necessity of using personnel in the hand work of positioning certain components on the circuit boards during the assembly of electronic devices. This work force could be put to use in a more skilled, productive and self-satisfying area.
In sum, the inability of prior art vacuum mounting heads of pick and placement machines to pick up, transport and place certain components on a circuit board during the assembly of electronic devices results in the following problems: breakage of certain components and circuit boards; time delays in the assembly of the electronic devices; increased labor costs; diminished and inconsistent quality of the assembled electronic devices; and time delays and expensive investments associated with customized machines.
Accordingly, there is a need for a simple, inexpensive nozzle for use with vacuum mounting heads in pick and place machines that provides for the pick up, transport and positioning of components, and especially of components that may be large, wafer-like in shape, relatively heavy, or non-flat topped on a circuit board of an electronic device.